1. Field of the Invention
The present invention relates to information transmitting and receiving equipment, and more particularly to equipment for transmitting and receiving the information contained in documents over communication lines such as telephone lines.
2. History of the Prior Art
It is known to transmit the information contained in documents over communication lines such as telephone lines to a remote location where copies of the documents are reconstructed. Such "electronic mail" or facsimile systems typically scan the documents to provide electronic representations of the information contained therein with the representations being transmitted over the telephone line in the form of digital data. At the receiving end of the communication line the digital data may be used to modulate print apparatus for reconstructing the document being transmitted.
Presently known electronic mail or facsimile systems suffer from various limitations which may prove to be a substantial disadvantage for certain applications. One of the most serious limitations is the time required to transmit the data over the communication line. The data is typically presented in serial binary form to the communication line. While compression schemes may be employed, the data is typically in non-coded form. The practical result is that it may require as much as five minutes or longer to transmit a single page. Documents ten pages in length or greater may require as long as an hour or more to transmit. Aside from the substantial time required for an operator to present the document for scanning and transmission, further problems are created by the fact that the original document must be kept at the facsimile transmitter for a substantial period of time in the case of lengthy documents. This may take a substantial toll in man-hours in a given operation such as where clerical personnel who travel from a distant location to transmit the document must return with the original document and therefore must remain at the facsimile transmitter until transmission is completed.
One solution to the problem of tying up the original document during the lengthy transmission thereof is to translate the information contained in the document into electronic signals and store the signals. This frees the original document for removal as soon as translation is completed. Depending upon the length of the document, however, a substantial amount of information storage space may be required. For example, one page of non-coded information can require as much as six million bits of storage space. When multiplied by the many pages of a lengthy document, this translates into memory sizes which may be prohibitively large and costly.
Various types of imaging apparatus including copiers, printers and combinations thereof have been employed in connection with facsimile systems in an attempt to provide various improvements to such systems. However, such arrangements have been unable to provide practical solutions to the problems noted above. Examples of such arrangements are provided by IBM Technical Disclosure Bulletin, Vol. 15, No. 10, March 1973, pp. 3259 and 3260 where a light beam is used to scan a document placed on the document glass in a xerographic copier-printer to generate an electronic facsimile of the scanned image, and U.S. Pat. No. 3,597,071 of Jones which shows a reproduction system with a plurality of different imaging input devices including facsimile transmission means.
Accordingly, it is an object of the present invention to provide improved apparatus for use in the communication of documents.
It is a further object of the invention to provide improved apparatus for transmitting facsimiles of documents.
It is a still further object of the invention to provide an improved copier-printer system which may be used in the transmission and receipt of document facsimiles.